The subject invention relates to a one-piece electrical contact, and in particular to a spring-loaded contact which can be mounted to a printed circuit board.
It is common in certain applications, for example, in the application of the portable hand set telephone, to have an electrical connection between a charging unit of the base portion of the telephone connected to the battery of the hand-held phone. Such an electrical connector is usually comprised of a spring contact portion, which is cylindrical in shape and includes a compression spring mounted within the cylinder, and a plunger contact portion held to the cylindrical portion yet spring loaded by the spring. The contact is surface mountable to a printed circuit board, whereby upon placement of the handset in the base or cradle of the telephone, the contacts on the handset engage and deflect the spring-loaded portion of the contact in the base to charge the battery in the handset.
While this electrical contact is suitable for the application as described, in that the contact has to be somewhat rigid and self-sustaining, the contact can be expensive due to the many expensive components of the contact as well as the labor intensiveness of its manufacture.
Another prior art connector system is shown in PCT Publication WO96/28865. While this connection system is suitable for the application in which it is disclosed, other applications have arisen requiring a modification as mentioned above.
Other contact systems, for example, U.S. Pat. Nos. 5,362,262; 5,427,545; and 5,520,548 show contact systems having an internal movable portion for contact with a pin, with an outer box-shaped backup member.
The objects of the invention have been accomplished by providing an electrical contact comprised of a first contact portion and a second contact portion, and an intermediate spring portion therebetween. The first contact portion is movable relative to the second contact portion through the spring, between a first position where the spring is in a free state, and a second position where the spring is deflected and the first and second contact portions are electrically interconnected. This provides that the electrical path between the first and second contact portions is shortened.
In the preferred embodiment of the invention the spring is sinuous in shape and the first contact member is a plunger contact. Furthermore, the second contact member is defined as a printed circuit board contact.
Also in the preferred embodiment, the spring portion is a sinuous spring which lies in a plane. A rear wall is positioned adjacent to the spring, electrically connecting the second contact portion, and having contact surfaces positioned adjacent to the first contact portion. The first contact portion extends integrally from a first end of the sinuous spring and the second contact extends integrally from a second end of the sinuous spring. The first contact portion extends integrally from a first end of the sinuous spring and the first contact portion is directed in a plane extending towards the contact surfaces, whereby when the first contact member is engaged, the sinuous spring is deflected, and the first contact member is directed into engagement with the contact surfaces. The rear wall is integrally formed with the second contact by a reverse bend, with the rear wall lying in a plane parallel with the sinuous spring. The contact surfaces are defined by rail portions being bent from the rear wall and having edges positioned adjacent to the spring. The electrical contact furthermore has a front wall defined by a second reverse bend adjacent the first contact portion and is positioned in a plane substantially parallel with the sinuous spring.
In yet another embodiment of the invention, a one-piece contact is comprised of a first contact portion and a second contact portion, and an intermediate spring portion therebetween. The first contact portion is movable relative to the second contact portion through the spring, and the contact further comprises an integral rear wall extending from the second contact portion through a reverse bend. A front wall portion extends integrally from the rear wall portion through a second reverse bend.
In the preferred embodiment of the invention, the second reverse bend is provided with an opening, and the first contact member is a plunger contact, extending upwardly through the opening. The first contact portion is movable relative to the second contact portion through the spring, between a first position where the spring is in a free state, and a second position where the spring is deflected and the first and second contact portions are electrically interconnected, whereby the electrical path between the first and second contact portions is shortened. The spring portion is a sinuous spring which lies in a plane. The second contact member is a printed circuit board contact.
Preferably, the first contact portion extends integrally from a first end of the sinuous spring and the first contact portion is directed in a plane extending towards the contact surfaces, whereby when the first contact member is engaged, the sinuous spring is deflected, and the first contact member is directed into engagement with the contact surfaces. The contact surfaces are defined by rear wing portions being bent from the rear wall and having edges positioned adjacent to the spring. The wing portions are defined by a transverse bend, with the edges being positioned in a plane substantially parallel with the spring. The electrical contact further comprises front wing portions extending from the front wall with edges being positioned in a plane substantially parallel with the spring, whereby the front and rear wing portions define a guide channel for the deflection of the sinuous spring.